1. Field of the Invention
The invention relates generally to the type of wastewater treatment system in which wastewater microorganisms are permitted to grow on a medium supported in a vessel containing the wastewater being treated but more specifically to a novel medium and medium support arrangement for such a system operating under aerobic conditions.
2. Background of the Invention
In aerobic wastewater treatment systems of the kind in which microorganisms are permitted to grow on a medium, it has been known to support the ends of relatively straight fibrous strands having tiny loops on a frame which permits a great number of such strands and having substantial surface area to be held vertically and closely spaced apart in a vessel holding the wastewater being treated. Such a system is shown in literature distributed by Ringlace Products, Inc. of Portland, Oreg. and which illustrates the company's "Ringlace.TM." strand product made of polyviniylidane chloride fibers.
Another system of the kind being described is shown in U.S. Pat. No. 5,262,051 in which bundles of synthetic fiber provide surface area for the growth of microorganisms and are illustrated being supported in a zig-zag fashion on a frame which in turn is supported within a vessel containing the wastewater being treated. Useful background information is also given in the '051 patent.
U.S. Pat. No. 5,500,111 illustrates a growth supporting medium incorporating continuous S-shaped portions and, as shown in FIG. 5 of the '111 patent, is made up as a collection of individual, short, spiral shaped units which are randomly placed in a vessel in which the wastewater is treated.
In FIG. 1 of U.S. Pat. No. 5,389,247, there is also shown a configuration in which synthetic ribbon-like contact members having a large number of projecting fluffs or loops are supported in a vertical sinusoidal array.
In summary, it can be seen that there have been many prior attempts to gain surface area in bacteria supporting medium by varying the kind of medium on which growth takes place and the manner in which the medium is supported in order to gain sufficient treatment of water. Prior attempts have also sought to provide a medium that can be made economically and that minimizes the need for cleaning and backwashing.
Accordingly, it is an object of the invention to provide a further improved system in which a uniquely configured medium is employed in the vessel in which the wastewater is treated and to use this medium as a means for obtaining a substantial increase in the surface area available for growth of microorganisms. Other objects will become apparent as the description proceeds.